The BBC's strategy chief James Purnell has questioned claims about the amount of time licence fee evasion takes up in magistrates courts, as MPs prepare to vote on the issue.

Purnell, the BBC's director of strategy and digital, said people not paying the licence fee accounted for just 0.3% of court business.

Supporters of a change in the law, pushed by more than 150 MPs from all parties and led by Tory backbencher Andrew Bridgen, claimed that more than 10% of magistrates cases are taken up by people not paying the licence fee, leading to the imprisonment of up to 70 people a year.

Purnell said: "We want to look at it based on the facts. For example, one of the facts that has been used is that this is taking up 10% of court cases.

"Actually, we think once we look at the facts it may well turn out that the time is much less than that.

"The last fact we saw was that it takes up 0.3% of time, because most of these cases are processed pretty quickly, about three minutes on average. We want to look at the facts."

Purnell, speaking to Eddie Mair on Radio 4's PM programme on Monday, said BBC executives had met with Bridgen last week to discuss the issue.

Labour indicated on Monday that it is broadly supportive of plans to decriminalise non-payment of licence fees, currently £145.50 a year.

However, no change in the law will take place before a consultation of up to a year, which will take place alongside negotiations around the renewal of the BBC's charter and a new licence fee.

Bridgen told PM: "Magistrates have been calling for the decriminalisation [of the licence fee] for 20 years. They detest having to spend so much time criminalising people whose only crime is having no money.

"Obviously it is going to cost the BBC more to collect their debts, but it is costing the state an awful lot of money criminalising these people – including putting potentially 70 people a year in prison."

Purnell, who has previously said decriminalisation could cost the BBC up to £200m in lost revenues, said it was "not for me to say" what Bridgen's intentions were behind the amendment.

He said the Tory MP "clearly has concerns about the magistrates courts and the prison system and that's one we are happy to look at."

Purnell said the BBC was content with the amendments as they will go before MPs on Tuesday.

"What we were nervous about was that this would be done in a rush without properly looking at the pros and cons of different systems," said Purnell, a former Labour MP and culture secretary.

"The government has the option of going for a civil system, a hybrid system, which would mix civil and criminal penalties, or keeping the system as it is. That is exactly what we have argued for all along," he said.

"What we said was it would be a huge risk to move now to a different system, which is what the original amendments tabled said. We were very worried that could have led to a big rise in evasion."

"The difference between us and the utilities is we can't stop people consuming, we can't switch people off. We have got to have a system with a proper deterrent.

He added: "We don't want to see anybody going to prison either. We are very happy to work with the government to see whether it could be improved or an alternative that's better."

Purnell admitted the corporation had not expected the issue of decriminalisation to come up so soon.

"This is something we always thought should come up in charter review, we didn't expect it to come up through this committee and this bill, but it's absolutely fine for it to come up that way. It's fine for parliament to make any decisions it wants to."

A BBC spokesman said: "The BBC is content that this proposal balances a timely examination of this issue with a proper review of the options, while not taking any decisions prior to charter review."

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